Asymmetric epoxidation of α,β-unsaturated aldehydes catalyzed by a spiro-pyrrolidine-derived organocatalyst

The asymmetric epoxidation of α,β-unsaturated aldehydes, catalyzed by a spiro-pyrrolidine (SPD)-derived organocatalyst, has been accomplished with good diastereoselectivities (up to dr >20:1) and with high to excellent enantioselectivities (up to 99% ee).

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(((2S,3S)-3-Phenyloxiran-2-yl)methanolC9H10O2[α]D20 = −47 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-(4-Bromophenyl)oxiran-2-yl)methanolC9H9BrO2[α]D20 = −32.0 (c 0.41, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-(4-Chlorophenyl) oxiran-2-yl)methanolC9H9ClO2[α]D20 = −38 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-(2-Fluorophenyl)oxiran-2-yl)methanolC9H9FO2[α]D20 = −23 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-(3-fluorophenyl)oxiran-2-yl)methanolC9H9FO2[α]D20 = −44 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-(4-Fluorophenyl)oxiran-2-yl)methanolC9H9FO2[α]D20 = −35 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-(p-Tolyl) oxiran-2-yl)methanolC10H12O2[α]D20 = −36 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-(Naphthalen-1-yl) oxiran-2-yl)methanolC13H12O2[α]D20 = −66 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-Methyloxiran-2-yl) methyl 4-nitrobenzoateC11H11NO5[α]D20 = −14 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-Ethyloxiran-2-yl) methyl-4-nitrobenzoateC12H13NO5[α]D20 = −23 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

((2S,3S)-3-Propyloxiran-2-yl) methyl-4-nitrobenzoateC13H15NO5[α]D20 = −32 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3S)

(S)-(3,3-dimethyloxiran-2-yl) methyl-4-nitrobenzoateC12H13NO5[α]D20 = −22 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (1S)

(S)-1-Oxaspiro [2.4] heptan-2-ylmethyl-4-nitrobenzoateC14H15NO5[α]D20 = −17 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (1S)

((2S,3R)-3-Heptyl-3-methyloxiran-2-yl)methyl 4-nitrobenzoateC18H25NO5[α]D20 = −11 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (2S,3R)

(5R,6R)-6-((tert-Butyldiphenylsilyl)oxy)-1-azaspiro[4.4]nonaneC24H33NOSi[α]D20 = −22 (c 1.0, CHCl3)Source of chirality: the organocatalystAbsolute configuration: (5R,6R)